fatal stabbing, a trial heard.Mary Smullen, 46, is accused of trying to cover-up the alleged involvement of Robbie Smullen, 23, in murdering Barry Dixon.The court had heard how she rushed round to a Perth flat to find Barry, 22, lying badly injured on a mattress.The flat was occupied by her son’s “on/off” partner, Shannon Beattie, 25, who previously told the trial she’d witnessed Robbie Smullen stab Barry in the chest.The High Court in Edinburgh was earlier played a transcript of Mary Smullen